Background Gastrointestinal stromal tumors (GIST), one of the most common mesenchymal tumors of the gastrointestinal tract, prior to routine immunohistochemical staining and the introduction of tyrosine kinase inhibitors, were often mistaken for neoplasms of smooth muscle origin such as leiomyomas, leiomyosarcomas or leiomyoblastomas. Since the advent of imatinib, GIST has been further delineated into adult- (KIT or PDGFRα mutations) and pediatric- (typified by wild-type GIST/succinate dehydrogenase deficiencies) types. Using varying gender ratios at age of diagnosis we sought to elucidate prognostic factors for each sub-type and their impact on overall survival. Methods This is a long-term retrospective analysis of a large observational study of an international open cohort of patients from a GIST research and patient advocacy's lifetime registry. Demographic and disease-specific data were voluntarily supplied by its members from May 2000-October 2010; the primary outcome was overall survival. Associations between survival and prognostic factors were evaluated by univariate Cox proportional hazard analyses, with backward selection at P < 0.05 used to identify independent factors. Results Inflections in gender ratios by age at diagnosis in years delineated two distinct groups: above and below age 35 at diagnosis. Closer analysis confirmed the above 35 age group as previously reported for adult-type GIST, typified by mixed primary tumor sites and gender, KIT or PDGFRα mutations, and shorter survival times. The pediatric group (< age 18 at diagnosis) was also as previously reported with predominantly stomach tumors, females, wild-type GIST or SDH mutations, and extended survival. "Young adults" however formed a third group aged 18-35 at diagnosis, and were a clear mix of these two previously reported distinct sub-types. Conclusions Pediatric- and adult-type GIST have been previously characterized in clinical settings and these observations confirm significant prognostic factors for each from a diverse real-world cohort. Additionally, these findings suggest that extra diligence be taken with "young adults" (aged 18-35 at diagnosis) as pediatric-type GIST may present well beyond adolescence, particularly as these distinct sub-types have different causes, and consequently respond differently to treatments.

Purpose:To quantify gastrointestinal stromal tumor (GIST) patients’ preferences for reducing treatment toxicities and the likely effect of toxicities on patients’ stated adherence.Methods:English-speaking members of the Life Raft Group, a GIST patient advocacy and research organization, aged 18 years and older, completed a web-enabled survey including a series of treatment-choice questions, each presenting a pair of hypothetical GIST medication toxicity profiles. Each profile was defined by common or concerning toxicities verified via pretest interviews including: severity of edema, diarrhea, nausea, fatigue, rash, hand-foot syndrome, and heart failure; and risk of serious infection. Each subject answered 13 choice-format questions based on a predetermined experimental design with known statistical properties. Subjects were asked to rate the likelihood that they would miss or skip doses of medications with different toxicity profiles. Random-parameters logit was used to estimate a relative preference weight for each level of toxicity.Results:173 subjects completed the survey. Over the ranges of toxicity levels included in the study, heart failure was the most important toxicity. Edema was the least important. For all toxicities, reducing severity from severe to moderate was more important to subjects than reducing severity from moderate to mild. Reducing heart failure from moderate to mild and diarrhea from severe to moderate had the largest effects on subjects’ evaluation of adherence.Conclusions:All toxicities included in the study are important to patients. Treating or reducing severe toxicities is much more important to patients than treating or reducing moderate toxicities. Focused reductions of certain toxicities may improve treatment adherence.

Background The use of imatinib, sunitinib, and regorafenib has transformed the treatment of advanced GIST. Sunitinib and regorafenib improve progression free-survival in the second (2L) and third (3L) line, respectively, compared with placebo. However, the impact of these agents on overall survival (OS) is unclear. Methods The Life Raft Group (LRG) patient registry contains records from 1716 GIST patients; 526 have advanced to at least 2L treatment. Patient-reported treatment and outcome data were examined to determine treatment patterns and their impact on OS. Results Median OS from start of 2L therapy was 32.4 months for sunitinib (n = 436) compared with 27.1 months for patients treated with any other 2L drug (n = 74, p = 0.023, HR 1.377) and 16.8 months for patients who never received sunitinib in any treatment line (n = 42, p = 0.028, HR 1.52). In patients reporting progression in 2L, the median OS in patients subsequently receiving 3L regorafenib (n = 53, 26.2 months) was longer than that of 3L patients who never received regorafenib in any line of therapy (n = 174, 14.3 months, p = 0.0002, HR 2.231), and was longer than that of patients who received any other 3L treatment (19.8 months, p = 0.044, HR 1.525). OS for advanced GIST patients in the LRG registry has improved over time ( p = 0.0013), correlated with the increased use of TKIs in ≥ 2L settings. Conclusions In our analysis, sunitinib and regorafenib significantly improved OS compared with patients who never received these agents. Our data also support the hypothesis that the use of KIT/PDGFRA inhibitors, including non-approved agents, has improved OS for patients with imatinib- and sunitinib-resistant GIST. Electronic supplementary material The online version of this article (10.1186/s13569-019-0114-5) contains supplementary material, which is available to authorized users.

Introduction: Rectal gastrointestinal stromal tumor (GIST) is rare and comprises about 3% of GIST. Methods: Registry data was collected by the Life Raft Group June 1976 to November 2017. All patients had a histologic GIST diagnosis. Demographic, clinicopathologic, and clinical outcome data were patient reported. Recurrence-free survival (RFS) was analyzed using the Kaplan-Meier method and Cox regression analysis.Results: Of 1798 patients in the database, 48 had localized rectal GIST (2.7%).Patients were frequently male (58.3%) and non-Hispanic whites (58.3%). Median age at diagnosis was 52 years. Most patients (77%) were diagnosed in the imatinib era (2001 to current). Over half (54.2%) of the cohort had mutation testing and all profiled tumors possessed KIT mutations (exon 9: 7.7%, exon 11: 88.5%, and exon 13: 3.8%). Most evaluable patients (26/28; 92.9%) had high-risk disease (modified NIH criteria) and nearly all patients (95.8%) received imatinib. Median follow-up was 8.8 years (range, 0.3-30.7) and overall RFS was 8.0 years (95% CI, 2.9-13.1). Thirty-two percent (12/37) of patients in the post-imatinib era developed recurrent disease.Diagnosis in the imatinib era was associated with improved RFS (HR = 0.22, 95% CI, 0.08-0.62; P = .004) in the multivariable model. Conclusion:We find that disease recurrence remains prevalent in one-third of patients treated during the imatinib-era. K E Y W O R D S gastrointestinal stromal tumor, imatinib, rectal mass, submucosal tumor

ObjectivesSelf-reported progression was evaluated as a predictor of survival in patients with metastatic gastrointestinal stromal tumor (GIST).MethodsThis is a follow-up of an open cohort study of Life Raft Group (LRG) members with a diagnosis of KIT-positive metastatic GIST receiving imatinib from May 2000–December 2007 reporting their subjective response to therapy by completion of an internet-based questionnaire. Subjects received ≥ 1 year of imatinib and reported an initial positive response. Members reporting stable disease or progression were excluded. Self-reported progression-free survival (srPFS) was compared with overall survival (OS) and analyzed by starting and last reported dose.ResultsOne hundred sixty-nine subjects reported a mean starting dose of 527.8±177.9 mg/d at a mean age of 53.8±11.6 years at initial diagnosis. Of those reporting progression, 66% died versus 11% of those not reporting progression (P < 0.0001). When analyzed by last reported dose, a median srPFS benefit of 27.3 months was observed for the >400 mg/d group (P = 0.0017). Sixty-two percent of subjects who initiated therapy at >400 mg/d reported a dose reduction. When analyzed by last reported dose, a significant benefit in OS (P = 0.0229) and srPFS (P = 0.0069) was observed for subjects taking 600 over 400 mg/d.ConclusionssrPFS strongly correlated with OS. Significant advantages were observed when last reported dose was considered, as was higher daily dose. These observations suggest that careful escalation to intermediate daily doses should be investigated further for its potential to reduce the incidence and severity of adverse events, but also as a strategy against developing secondary resistance to imatinib.